Diesel Electric Propulsion

[Julie Mor]

Originally Posted by a64pilot

My neighbor has a Lagoon 38 or 40, not sure, He says the thing has a 12KW generator?
Wouldn't that almost drive the boat?

This is where my thoughts were going when I started the thread. The information I have read so far seems to indicate that if you're going to put a generator on a boat, the possibility exists the boat can be retrofitted with an electric motor that can take the place of a diesel auxiliary. It all depends on your use and/or how much you are willing to spend.

Oceanvolt's brochure states if you have a Volvo or Yanmar sail drive, their electric motor can be installed in place of a diesel with just the use of their flange. If you already have a generator, it wouldn't be that big a deal to go this route, if you need to repower, and not lose a thing.

In the new boat market, I imagine waving the benefits of this technology (quite, versatile, low maintenance, green, etc) in front of deep-pocket buyers. That's where I believe it will take off, as long as power and reliability are there.

[Julie Mor]

I was reading a section in a book by Nigel Calder regarding diesel electric propulsion. What I found interesting is he said (if I understood this right) if you design and size your battery/inverter system properly so that it can handle start-up loads, the generator needed to have a fully functional hybrid setup - that is one that can perform pretty much the same as a diesel auxiliary - can be as little as 25% the size needed if the generator is sized to handle start-up loads on its own.

Of course, the implications one can take from that are head turning. I imagined a forward-looking boat building company taking that and figuring out a way to replace the standard diesel auxiliary/battery bank normally installed and replace it with a D-E hybrid system, one that creates 120v power at sea, for a small increase in price. The general appeal would be huge.

We're already catering to the push-button, make-it-like-home consumer. But what isn't there is the electrical conveniences of home. Imagine offering that in a 30 footer. Bene and other companies have been focused on making the sailboat more like home. This is just the next logical step. Once the mass produced boats get on the wagon, it's just a matter of time before prices come down and make a D-E repower a no-brainer.

[Sailmonkey]

Streyr already builds a "shaft" generator onto its small engines.


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[downunder]

Originally Posted by Julie Mor

I was reading a section in a book by Nigel Calder regarding diesel electric propulsion. What I found interesting is he said (if I understood this right) if you design and size your battery/inverter system properly so that it can handle start-up loads, the generator needed to have a fully functional hybrid setup - that is one that can perform pretty much the same as a diesel auxiliary - can be as little as 25% the size needed if the generator is sized to handle start-up loads on its own.

Of course, the implications one can take from that are head turning. I imagined a forward-looking boat building company taking that and figuring out a way to replace the standard diesel auxiliary/battery bank normally installed and replace it with a D-E hybrid system, one that creates 120v power at sea, for a small increase in price. The general appeal would be huge.

We're already catering to the push-button, make-it-like-home consumer. But what isn't there is the electrical conveniences of home. Imagine offering that in a 30 footer. Bene and other companies have been focused on making the sailboat more like home. This is just the next logical step. Once the mass produced boats get on the wagon, it's just a matter of time before prices come down and make a D-E repower a no-brainer.

Beneteau did it with their Lagoon 420's some time back and were burnt. Search for some details. Most of the hybrids have been converted back to diesel I believe.

None of the big production manafucturers have sorted it as yet cost effectively.

[BigBeakie]

Originally Posted by downunder

Beneteau did it with their Lagoon 420's some time back and were burnt. Search for some details. Most of the hybrids have been converted back to diesel I believe.

None of the big production manafucturers have sorted it as yet cost effectively.

The "Lagoon experience" with EP is often cited as demonstrating that EP doesn't work, or can't work, or is not ready yet, or is too something or other. Whatever.

I'm not sure the real story of the massive Lagoon failure with EP has been told, (and I'm not the one to due justice to it) but from what I have heard, the reasons why the E-Motion system did not perform to specification are not because the technology is not capable, but because there were changes to the system spec by those who were not as well versed in EP as the system designer. Major parameters of the system design by Telford were changed (such as operating voltage) by those who thought they knew better at Lagoon, and the result was an abortion, with many unhappy Lagoon clients.

It is instructive that the Lagoon clients with the original E-motion system are still happily using the EP system as originally designed, as far as I know. I'm happy to be corrected on that, as obviously my information is second or even third hand.

At least Lagoon came to the party and fully supported the clients to replace the electric system with what they knew, the original diesels. The takeaway message is that if you're going to do something, do it right

[Scout 30]

I think the Elco systems are worth checking out for anybody that needs to repower. They've developed a plug & play system & make a motor big enough for just about any sailboat. Plus, they look cool!


Elco Motor EP-1200#

[skipmac]

Originally Posted by Scout 30

I think the Elco systems are worth checking out for anybody that needs to repower. They've developed a plug & play system & make a motor big enough for just about any sailboat. Plus, they look cool!


Elco Motor EP-1200#

Very interesting. First commercially available "marine" system I've seen with some high power options, BUT:

- The EP7000 which is the model I would need for a 42' boat is $17,375 with charger. I could buy a new engine and transmission for less.
- Max range under power with 9 X 8D batteries (about 140 lbs each) 36 nm at 6 kts. Run up to hull speed and that drops to 20 nm
- Add a generator of 10-16 KW to get decent cruising range for an additional $10-$15,000. Now you have over double the cost of a new ICE, more weight on the boat than just going with diesel alone and you still have all the engine maintenance to deal with plus the generator section to go with it.

Don't get me wrong. I would love to switch to electric but I'm not willing to accept a range of under 40 nm or the need to add a generator on top of the electric motor which doubles the cost.

Also I just cannot understand why a "marine" electric motor is so expensive. I can buy the electric motor for my Prius for under $1000 and those regularly run years and years and 300,000 miles trouble free. Of course that doesn't include controls and charger but I cannot imagine those would ad $16,000 to the total cost.

[Scout 30]

I think this is only a viable option for someone who already has or is installing a generator which gives you a range of several hundred miles. Also, you could probably go with the 4000 which is considerably cheaper. That being said I have to agree with you on the price. A diesel is much more complicated & I would think it would be much more expensive to build so why do these cost as much as an equivalent diesel. I think that if they could significantly undercut diesel prices they would increase their market share dramatically.

[leftbrainstuff]

Originally Posted by Scout 30

I think this is only a viable option for someone who already has or is installing a generator which gives you a range of several hundred miles. Also, you could probably go with the 4000 which is considerably cheaper. That being said I have to agree with you on the price. A diesel is much more complicated & I would think it would be much more expensive to build so why do these cost as much as an equivalent diesel. I think that if they could significantly undercut diesel prices they would increase their market share dramatically.

Products that have evolved over decades and sell in the millions are quite cheap to manufacture. Much of the cost of a diesel engine or transmission comes from the supply chain from raw materials to selling to and supporting the end user. Warranty risks are also relatively low.

Electric motors are easy to make but tend to use some expensive materials. High power electric controllers are also expensive to produce. Much of those costs are only amortised over relatively small volumes. Pricing is also related to market risk. All electric drives for sailboats are only numbered in the hundreds (maybe thousands...) at this time.

Pricing of most products is also determined by what the market can support. I suspect all electric drives are marketed to early adopters who will often support the higher costs.

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[Stumble]

Originally Posted by Julie Mor

This is where my thoughts were going when I started the thread. The information I have read so far seems to indicate that if you're going to put a generator on a boat, the possibility exists the boat can be retrofitted with an electric motor that can take the place of a diesel auxiliary. It all depends on your use and/or how much you are willing to spend.

Oceanvolt's brochure states if you have a Volvo or Yanmar sail drive, their electric motor can be installed in place of a diesel with just the use of their flange. If you already have a generator, it wouldn't be that big a deal to go this route, if you need to repower, and not lose a thing.

In the new boat market, I imagine waving the benefits of this technology (quite, versatile, low maintenance, green, etc) in front of deep-pocket buyers. That's where I believe it will take off, as long as power and reliability are there.

This is sadly not true. The real issue is that while you may normally only need a fraction of the power available from a diesel instal, you always need to have it available. There is just no way of getting around the fact that from time to time boats will need massive amounts of power. Wether is powering off a lee shore, towing another boat home, fighting against a current, or frankly just maintaining hull speed under power to make landfall before night.

Reducing your generator to 25% the current drive motor size will work so long as everything is fine, and you just want to putter around at 3kn, but when you want full power you won't have it.

From Panbo
"One of the hybrid issues that Nigel has written about in Professional Boatbuilder (search back issue index here) is the need for top end power in rough seas and high winds, and apparently his testing in Sweden is proving the truth of that concept. The last knot of displacement boat speed, sometimes left out of early hybrid attempts, takes a heck of lot more power, and it's the same power needed to make way when things get nasty. Which accounts in part for the hybrid boats that eventually went back to conventional propulsion systems. - See more at: Panbo: The Marine Electronics Hub: Nigel Calder update, charts & HyMar

Bill Southworth (the ceo of Hybrid Propulsion) is equally dubious of this concept. And of the whole 'electric boats need less hp' line of reasoning. At the end of the day shaft hp is shaft hp. There is just no way around it. And prop curves, boat speed, torque load are all interrelated. Which is why the HyMar wound up using seriel electric motors (two motors per shaft) to get decent performance. Which while technically ideal would be rediculiously expensive.


As always with electric drives the first thing to do is decide what you want it to do. If it's just putter out of the harbor then your fine. If you want it to replace your diesel for real propulsion then it won't work.

[skipmac]

Originally Posted by leftbrainstuff

Products that have evolved over decades and sell in the millions are quite cheap to manufacture. Much of the cost of a diesel engine or transmission comes from the supply chain from raw materials to selling to and supporting the end user. Warranty risks are also relatively low.

Electric motors are easy to make but tend to use some expensive materials. High power electric controllers are also expensive to produce. Much of those costs are only amortised over relatively small volumes. Pricing is also related to market risk. All electric drives for sailboats are only numbered in the hundreds (maybe thousands...) at this time.

Pricing of most products is also determined by what the market can support. I suspect all electric drives are marketed to early adopters who will often support the higher costs.

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I generally agree with most of this in general.

However, even with the economy of scale for cars vs boats I can't see that justifying a cost difference of 10 times or more.

Same with the rare earth magnets that are used in high efficiency electric motors. If they can make an ultra high efficiency electric motor/generator for a Prius for $1000 it shouldn't be that difficult to adapt the same technology for a marine unit for 2-3 times that at most.

You can purchase a heavy duty, continuous duty industrial electric motor for similar prices. So why not use one of these for a marine electric. If they are too susceptible to corrosion in the marine environment then give each customer a spare motor and charge an extra grand for the package.

Maybe I'm missing something but I just don't see why you can't sell a marine electric system for $5-$10,000.

[med]

One thing which has changed the equation a bit in recent years is the common rail and electronic controls on diesel engines. This results in good fuel efficiency over a very wide range of operating conditions. Even with a fixed pitch propellor this means that the engine is operating at over 95% of its highest efficiency from about 25% load to 95% load. With a variable pitch propellor this range can be extended a bit downwards.

Effectively only if you are running at considerably less than 20% load of your main engine would you gain by using a hybrid system.

Also check out the size of battery bank you will need. For example to power a 50ft 30tonne trawler at 8 knots you need approx 40KW. I.e. more than 3000 AH @ 12V per hour of cruising.

Then you need to recharge that lot. Most shore power connections where I am are limited to 5KW. I.e. at least 8 hours of recharge time per hour of motoring. And forget solar - you do not have enough acres of deck to be able to get anywhere close to enough power.

Cruise ships use electric drive in order to be able to pod the drives. This gives them greate manoeverbility which enables them to dispense with tugs when entering/exiting ports. As they enter and exit a port every day this makes for a significant saving. Also they vary the number of diesel engines they have on line according to the load they have - i.e. how fast they need to go to keep to schedule.

The navy use electric drive as a convenient way to couple together engines with very different characteristics from diesel generators for the normal plodding work to gas turbines (i.e. jet engines) which are less efficient for going very fast.

As a cruiser we want to minimize the number of engines we have on a boat.

[Sailingcouple13]

The Gunboat 55 is now standard with electric drives. The Diesel is available as a $75,000 option.

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[Scout 30]

I would like to repower with the Elco EP-2000. This motor has a continuous output rating of 8.5 kilowatts & provides an approximate range of 34 miles at 5.5 knots on 6 batteries without benefit of the generator. I'm just a coastal cruiser so this is about as far as I'd ever go in a day. The Elco website says that with a 5kw generator running you can cruise for 4 days nonstop at this speed. Of course I understand that these numbers are estimates & that there are a lot of variables but I have a small full displacement hull trawler with a 30' waterline length so 5.5 knots is easily achieved. My question is are these real world numbers? Does what Elco is saying make sense & can I expect these type of results?


Elco Motor EP-2000


https://www.facebook.com/Scout30OwnersGroup

[misfits]

Originally Posted by Scout 30

I would like to repower with the Elco EP-2000.

I think they make a nice product & they've been in the electric game for a long time. Their web site has all the pricing as MSRP. I've been trying to get a real world price for an EP-1200 & have had no friggin luck what so ever. They're quick to tell you how wonderful & green they are. I'll pass on the Kool-Aid.. Ask me how I really feel LOL